Intra-uterine environment influences glomerular number and the acute renaladaptation to experimental diabetes

Aims/hypothesis. We sought to test the hypothesis of whether low birth weig ht rats would have reduced glomerular number, higher systolic blood pressur e and an altered acute response to streptozotocin diabetes compared to norm al birth weight rats. Methods. Female offspring of Wistar rats fed an isocaloric diet containing either 6% casein (LPD) or 18% casein (NPD) in utero were studied. Birth wei ght, body weight, systolic blood pressure and urine albumin excretion were measured before and after streptozotocin diabetes. Glomerular number and vo lume were estimated after one week of diabetes. Results. The LPD rats were of low birth weight (5.4 +/- 0.5 g vs 6.4 +/- 0. 8 g, p < 0.0001) with higher systolic blood pressure (137 +/- 9 mmHg vs 120 +/- 7 mmHg, p < 0.0001) and reduced glomerular number (17 435 +/- 2074 vs 24 846 +/- 1864, p < 0.0001). The LPD rats had smaller kidneys (0.925 +/- 0 .009 g vs 1.200 +/- 0.173 g, p = 0.041) but similar glomerular volume to NP D control rats (1.11 +/- 0.15 . 10(6) <mu>m(3) vs 1.08 +/- 0.17 . 10(6) mum (3)). After 1 week of diabetes LPD rats had a greater proportional increase in renal size (diabetes 50 +/- 12% vs control 20 +/- 4%, p = 0.003). Insul in suppressed renal hypertrophy in both LPD and NPD rats but failed to supp ress glomerular hypertrophy in LPD rats (1.48 +/- 0.21 . 10(6) mum(3) vs 1. 03 +/- 0.23 . 10(6) mum(3) p = 0.015). Conclusion/interpretation. Abnormal intra-uterine environment reduces both renal size and glomerular number and influences the acute renal adaptation to experimental diabetes.